First Layer:

(BassLink, Volvo Emergency Kit; I recently picked up a Crossfire Satchel to put the Northrop Grumman Bag into)

Second Layer:

(The compartments to hold jumper cables, radar detector case, spot cleaning supplies, a few small convenience items)

Third Layer:

(The component board that houses the AVG-VDP, AVD-6210 and ND-BC2)

(The fourth layer is the stock compartment for the central locking, tire repair supplies etc.)